What is Diagnostic Sleep Testing?
Diagnostic sleep testing is a study performed during your sleep, recording of your brain waves, eye and chin movements, limb movements, chest wall and abdominal movements, breathing patterns, oxygen level, carbon dioxide levels, heart rate, heart rhythm and loudness of snoring whilst you sleep. Sometimes, in the setting of laboratory testing, there maybe video recordings of your sleep as well, which may assist in the diagnosis of other sleep disorders (eg parasomnias).
The assessment of these recorded patterns by a trained sleep specialist may allow for diagnosis of sleep problems (eg obstructive sleep apnoea, central sleep apnoea, sleep hypoventilation, periodic limb movements of sleep/restless leg syndrome) but may sometime also reveal other underlying medical disorders.
What Are The Types of Diagnostic Sleep Testing?
There are four categories of diagnostic sleep testing, ranging from type I to IV, with decreasing complexity of the study (and hence reducing number of signals and reducing sensitivity) from type I to type IV.
You may choose to do an in-laboratory diagnostic sleep study (type I testing), if you prefer to stay overnight at a hospital, either at Westmead Public Hospital or Westmead Private Hospital, both of which Dr Wu has affiliations with and would be able to review your results in person. This is the most sensitive and accurate form of diagnostic sleep testing.
Alternatively, if you prefer to have the study conducted in the comfort of your own home environment and your own bed, Dr Wu also offers a home diagnostic sleep study service run through his surgery. Dr Wu offers a type II home diagnostic sleep service (ie full overnight polysomnography with limited leads, without direct overnight observation). You will be required to come to the surgery on the day of your test and be set up by one of our trained staff. You will return home to sleep and return the equipment to us the next morning. Dr Wu will personally review each and every study in detail and also assess the quality of the study, and then generate an individualized report of the study.
A home diagnostic sleep study (type II study) has proven utility in diagnosing patients with a high pre test probability of obstructive sleep apnoea but may underestimate the severity of the disease by around 10%. Recent position paper published by Australasian Sleep Association based on a review of available literature endorsed type II study as part of a diagnostic pathway to rule in and rule out suspected obstructive sleep apnoea.
However, not all patients are suitable for type II diagnostic sleep testing. Some of these groups of patients include patients
- On regular use of supplemental oxygen
- Severe chronic obstructive pulmonary disease (COPD) with FEV1/FVC < 70% AND FEV1< 50%
- Awake oxygen level of <92%
- Suspected to have complex sleep disordered breathing eg, awake hypercapnoea, obesity hypoventilation syndrome, hypoventilation due to neuromuscular disease or chest wall disease, periodic breathing/Cheyne-Stokes respiration with a history of heart failure, chronic narcotic use
- Suspected other sleep disorders (eg narcolepsy, restless leg syndrome, parasomnia, REM related sleep behavioral disorder)
- Alcohol abuse
- Uncontrolled psychological or psychiatric disorders
- Severe intellectual disability
- Major communications difficulties
- Severe physical disability without inadequate carer attendance
- Unsuitable home environment
Dr Wu will discuss the costs, waiting times and appropriateness of these different testing methods with you during your consultation.
After the results of either of these sleep studies are available, we will organize a follow up appointment for you to see Dr Wu to discuss the results, diagnoses and management plan. If treatment has been recommended, further treatment testing maybe required, to ensure the efficacy of the therapy in treating the condition.
Why Have Your Home Diagnostic Sleep Study With Us?
There are many excellent reasons to have your home diagnostic sleep testing performed with us!
Our number one goal is to perform a home diagnostic sleep study of the highest quality and accuracy. We only perform type II home diagnostic sleep testing, as type III and type IV home sleep testing have reduced number of signals gathered and hence reduced sensitivity for the correct diagnosis of your sleep disorder. We utilise the most modern and up-to-date equipment for home diagnostic sleep testing. We regularly assess the quality of the signals from the study and the equipment, to ensure that the quality is maintained. If you are recommended to undertake a home diagnostic sleep study by Dr Wu, Dr Wu will always be the one that reviews and reports the study, which would allow the most appropriate treatment recommendation to be made for you. Dr Wu has no pecuniary interests in any devices used for treatment of obstructive sleep apnoea and will always recommend you the treatment options based on clinical indication and your personal preference.